One of the principal things that’s new about Nintendo’s Wii U gaming console is its WiiTV feature. WiiTV wasn’t quite ready when the console shipped last month, though — and even the version which is now available is a work in progress.

But one Wii U video feature was ready for the console’s launch: Netflix. On one level, that wasn’t surprising. You can stream Netflix to more than 800 different devices; it’s pretty much a baseline capability for an Internet-connected entertainment gadget, and it’s worthy of note when something doesn’t have it.

Netflix’s timely arrival on the Wii U did mean, however, that Netflix had to design, create and test the app well before the console was actually available. And creating a Netflix app for Wii U presented some new challenges, since this gaming system’s user interface is such a departure from the Wii and other consoles. I recently visited the company and learned about the process from the team responsible for the Wii U app, including Director of Product Innovation Chris Jaffe.

The degree of collaboration between Netflix and the hardware companies whose devices it supports varies from project to project. In this case, Netflix worked on its own: The only guidelines it had from Nintendo were a few general parameters such as how the app should allow the user to get back to the Wii U home screen.

The team knew that it had to make its service make sense on the Wii U’s GamePad — the console’s unique touch-screen controller, which serves as a satellite for the HDTV and behaves a little differently in every Wii U game and app. So it considered its options. Should the TV be the primary display for choosing and controlling streaming video playback? Should the GamePad? Or should they duplicate each other, an approach which Netflix calls mirroring?

It wasn’t clear. When something isn’t obvious, Netflix likes to do some testing with real live Netflix customers. But there was a catch: The company didn’t yet have a working Wii U or a GamePad, let alone a Netflix app to test.

Harry McCracken / TIME.com

Netflix’s fake foam GamePad.

So it worked around this little problem by faking a GamePad. The design team took a 7″ Samsung Galaxy Tab tablet and simply covered it with a printed GamePad with a hole in the middle for the tablet’s screen. Later, it upgraded to a three-dimensional fake GamePad made of foam, still with a hole for the Galaxy Tab. Those were the “GamePads” it showed to consumers, with a mocked-up version of the Wii U Netflix experience.

Netflix did some initial testing in San Francisco, then conducted a focus group in…Albuquerque. Why Albuquerque? Because the company’s home region, the Bay Area, skews too heavily to tech-savvy types rather than more everyday folk.

By doing this testing, Jaffe says, Netflix discovered that when the TV and GamePad displays differed too much “there was a very real whiplash problem” as users switched focus between the two screens.

Netflix

The final Netflix experience on the Wii U.

“Mirroring was largely the big win here,” says Jaffe: The test subjects, it turned out, preferred duplication between TV and GamePad. So that’s how the final version of the app works: The familiar Netflix interface with posters of movies and TV shows lives on both screens. There are some differences in details and color scheme, but they’re more alike than different, and you can either focus your attention on the controller or the TV. (You can also navigate either by touching the GamePad’s resistive screen or by using its physical controls.)

Of course, the TV and the GamePad don’t stay mirrored forever. Once something’s playing on the TV, the GamePad displays supplementary information, and you can continue to browse for other stuff without disturbing the current show. You can also flip the video from the TV onto the GamePad and watch there.

We got a wii u for xmas to replace our wii. We can no longer access netflx. Could it be a wifi issue. We have wifi, but maybe the modem isn't strong enough or something. Has anyone else asked you about this? I am completely irritated cause my main draw as a mom was to be able to watch netflix still.